For a rectangular channel section, Group I lists geometrical

For a rectangular channel section, Group I lists geometrical elements and Group II gives proportions for hydraulically efficient section.

Y_e is the follow depth corresponding to hydraulically efficient section. The correct match of Group I with Group II is

1. P-2, Q-4, R-1, S-3
2. P-3, Q-1, R-4, S-2
3. P-3, Q-4, R-1, S-2
4. P-3, Q-4, R-2, S-1

For hydraulically efficient rectangular section,
Top width, B = 2_{y_e}
Perimeter = B + 2_{y_e} = 4_{y_e}

Hydraulic radius, Re =	A
	P

=	2_{y_e}²	=	y_e
	4_{y_e}		2

Hyraulic depth,	A	=	2_{y_e}²	= y_e.
	T		2_{y_e}